plains and prairies (tall grasses) of central North America. Temperate grasslands
have hot summers and cold winters, and rainfall is moderate. The amount of
annual rainfall influences the height of grassland vegetation, with taller grasses
in wetter regions. As in the savanna, seasonal drought and occasional fires are
factors that affect biodiversity.
Figure 4.29 Temperate grassland food web
The soil is deep and dark, with fertile upper layers, and it is nutrient-rich
from the growth and decay of deep, many-branched grass roots. The rotted roots
hold the soil together and provide a food source for living plants. Seasonal
drought, occasional fires, and grazing by large mammals prevent woody shrubs
and trees from invading and becoming established. However, a few trees, such as